1. Field of the Invention
The present invention relates to an electric bike, and in particular to an electric bike with capability of self-charging.
2. Description of Prior Art
With the rapid increase in the price of petroleum and the importance of environmental protection, electric bike has become one of the green products popularized by the government because of its advantageous features such as no fuel consumption, no waste gas, low noise and low electricity consumption or the like. Thus, the electric bike has become a popular means of transportation recently. In addition to elders and women, students and working people gradually like to ride the electric bike.
Please refer to FIG. 1, which is a block view showing a conventional electric bike. As shown in this figure, the electric bike comprises a petal assembly 10A, a wheel 50A, a battery 20A, a driving unit 30A and a permanent magnet motor 40A. The battery 20A supplies a constant DC voltage. The driving unit 30a is electrically connected to the battery 20A for receiving the DC voltage outputted by the battery 20A to drive the permanent magnet motor 40A, thereby causing the rotation of the wheel 50A. Thus, a user can step on the petal assembly 10A of the electric bike to drive the wheel 50A to rotate. Alternatively, the battery 20A can supply the electricity necessary for driving the electric bike. Therefore, the electric bike can be driven by two ways based on the user's demands. That is, the user can step on the petal assembly 10A to drive the electric bike or rely on the battery 20A to supply electricity necessary for the electric bike. The user can choose one of the two ways for driving the electric bike based on his/her habit, the actual conditions of roads, practical demands or the like. Thus, the use of the electric bike becomes more flexible.
However, when the battery 20A of the electric bike is almost exhausted, it has to be charged, thereby supplementing the amount of electricity in the battery 20A for the next use. As a result, the user may worry about whether the amount of electricity in the battery 20A now is sufficient or not when riding the electric bike. Further, charging the battery 20A is carried out by connecting to utility power, which may increase the electricity fee and cause the discharge of greenhouse gases (such as carbon dioxide) indirectly.
Therefore, in order to overcome the drawbacks of prior art, the Inventor proposes an electric bike with capability of self-charging, which makes the electric bike to become a true green product.